1. Field of the invention
The present invention relates to regulating devices, especially for turboshaft engines for aircraft, and more particularly to regulators in which all the hydromechanical functions are integrated in one part, termed a fixed part, and the electrohydraulic functions are carried out by external components rigidly secured to the fixed part and connected electrically to sources of current and hydraulically to the fixed part of the regulator.
2. Summary of the prior art
The electrical connections of these electrohydraulic components are usually external to the regulator and to the hydraulic connection plate which may be fitted between the components and the fixed part of the regulator, and are made by means of electrical cables and connectors arranged on the faces of the equipment remote from the fixed part or on the side faces of the components.
The unit with the cabling is heavy, cumbersome and difficult to handle, and the assembly or taking down of the regulator involves connecting or disconnecting the electrical connections. These tasks take up a lot of time, are detrimental to the reliability of the unit and increase the risk of damaging the connectors and cables, which are very expensive to replace.
It would therefore be useful to be able to make the connections of the external electrohydraulic elements on the regulator or its hydraulic connection plate in a manner simultaneous with the positioning of the outer elements on the regulator. It would also be useful to be able to reduce the number of the necessary electric connectors, as well as the size of the cables, so as to make maintenance work on the regulator faster, more reliable and less costly.
In this respect, French Specification No. 2 592 432 has proposed regrouping all of the external electrohydraulic or electropneumatic equipment on the same flat surface of the regulator, and interposing between the fixed part and the external equipment an electrical connection plate constituted by a metallized printed circuit board. The hydraulic connections are made in a fluid-tight manner between the equipment and the fixed part through apertures in the printed circuit board.
However, this arrangement has a certain number of drawbacks as the printed circuit board has been found to be fragile under compression and, in addition, has a tendency to swell in contact with fuel. After a certain period of use, this may lead to the metallized areas of the board losing adherence. Moreover, such an arrangement requires contact means between the wires and the printed circuit which should be self-cleaning and, inevitably, form a weak point in the electrical circuit.